The main goal of this project remains the identification of patients at high risk of sudden death following recovery from myocardial infarction. An additional goal is the characterization of ventricular arrhythmias in subgroups of patients during this recovery period. Twenty-four hour tape recordings obtained just prior to hospital discharge and at intervals following discharge are used to detect and characterize the presence of ventricular arrhythmias. Analysis of the tapes is done by a well-established computer system which provides a comprehensive report describing the type, frequency and characteristics of ventricular arrhythmias. This extensive information is combined with other information such as an estimate of the size of the myocardial infarction and other clinical variables normally measured during hospitalization of patients with acute myocardial infarction. Based on the above information subgroups of patients are being followed to determine mortality as a function of important clinical characteristics.